Affect of Cast in Pipes in a 1m thick Raft Slab on shear
Affect of Cast in Pipes in a 1m thick Raft Slab on shear
(OP)
I am designing a 1m thick raft slab and the drainage guys have thrown in 100mm diameter cast in pipes all over the raft. See Attached images 1 & 2. Wondering how this will affect the shear in the raft and how i can go about calculating required shear reinforcement for a) the column and b) the pipes. I have read the presence of the pipes can be ignored however this doesn't seem right to me especially when columns are surrounded by pipes. Any feedback or pointers to get me in the right direction would be greatly appreciated. the Raft has an H20-150 Basic Matt throughout T&B.








RE: Affect of Cast in Pipes in a 1m thick Raft Slab on shear
...likely not an issue if you provide added reinforcing to accommodate shear and flexure. Can do a small FEM study to see if any stress risers, but, should be able to reinforce to accommodate this.
Dik
RE: Affect of Cast in Pipes in a 1m thick Raft Slab on shear
Pipes can be ignored. If this was not true, buried electrical ductbanks which are lightly reinforced and often subjected to vehicle traffic would be a disaster.
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RE: Affect of Cast in Pipes in a 1m thick Raft Slab on shear
There is a 10 storey building being supported on-top of this slab, with considerable loads on some of the columns. In the range of 5000-10000kN (ULTIMATE).
RE: Affect of Cast in Pipes in a 1m thick Raft Slab on shear
Dik
RE: Affect of Cast in Pipes in a 1m thick Raft Slab on shear
SRE, I don't see the relevance of your ductbank detail to the OP's mat foundation for a 10 storey building.
RE: Affect of Cast in Pipes in a 1m thick Raft Slab on shear
I used the ductbank example since it has a large amount conduit for it's size and is lightly reinforced.
Gets loaded as a beam when a roadway (in our area - with poor soil) settles but the adjacent road shoulders don't settle.
Easy to find a representative picture of a ductbank on the web.
No doubt a better example can be found.
Also, I made my post 8 minutes before the OP told us the foundation was for a 10 storey building.
www.SlideRuleEra.net
www.VacuumTubeEra.net
RE: Affect of Cast in Pipes in a 1m thick Raft Slab on shear
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Affect of Cast in Pipes in a 1m thick Raft Slab on shear
RE: Affect of Cast in Pipes in a 1m thick Raft Slab on shear
Join Pat's Pub and buy us a beer... It's hot (somewhere) and we're thirsty...
Dik